Study of the structure of degummed Antheraea assamensis (muga) silk fibre

The paper discusses a special type of silk (muga silk) produced by the moth Antheraea assamensis (Lepidoptera: Saturniidae), which is available in the north east region, particularly in Assam, India. The structure of the degummed muga silk fibre is characterised by spectroscopy and X‐ray diffraction. An attempt has been made to establish a correlation between the orientation of the protein of the fibre and the mechanical properties of the fibre. Inter‐conversion of the α‐ and β‐phases of proteins is very common, and in some cases, both the phases may be present. Since muga silk is a protein fibre, there is a strong possibility of exhibition of this inter‐conversion property. The results show that the structure of muga fibre is made up of four molecular chains contained in a primitive tetrahedral cell with an average cell edge a _o = b ₀ = 746 pm and c ₀ =738 pm (fibre axis) and lattice number 8. The space group of the α‐phase is P4₁, with screw axis 4₁. The α‐phase accounts for rigidity and crystallinity, while the β‐phase accounts for extensibility and the amorphous state of the fibre.